A007499 Number of cases considered in a particular algorithm for enumerating hexaflexagrams. (Formerly M0598)

2, 3, 4, 12, 20, 55, 127, 371, 1037, 3249, 10071, 32913, 108112, 363618, 1233938, 4244102, 14716095, 51480027, 181312939

Offset

1,1

Comments

See O'Reilly reference for precise definition.

References

Thomas J. O'Reilly, Classifying and Counting Hexaflexagrams, J. Rec. Math., 8 (1976), 182-187.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=1..19.

Sean A. Irvine, Java program (github)

Thomas J. O'Reilly, Classifying and Counting Hexaflexagrams, J. Rec. Math., 8 (1976), 182-187. [Annotated scanned copy]

Crossrefs

Cf. A000207.

Sequence in context: A331945 A275067 A295620 * A117555 A243392 A239943

Adjacent sequences: A007496 A007497 A007498 * A007500 A007501 A007502

Keyword

nonn,more

Author

N. J. A. Sloane, Robert G. Wilson v, circa 1976.

Extensions

Title clarified and a(11)-a(19) from Sean A. Irvine, Jul 12 2022

Status

approved